It’s freezing but that flock of ducks is standing barefoot on an icy pond. Why don’t they have frostbite? Turns out, ducks (any many other birds) have something in their legs humans don’t, rete mirabile.
Brrrrr! image: Capri23auto (pixabay.com)Rete mirabile at work, warming blood coming in from the feet and cooling blood going out into those webbed toes. A perfect internal heat exchanger for standing on the ice.
